iOS 4.0 Error 13?

I'm 3.1.2 8GG IBen with blackra1n.
I wanted to update to 4.0, so I tried restoring on iTunes. At the end it said that my Ipod could not be restored.
I downloaded the 4.0 firmware for 2G, and tried Shift Restore.
But I'm getting an error 13.
Now My iPod's screen is On, but it shows nothing. It's in Recovery mode.

1. Turn the iPhone or iPod OFF.
2. Plug in the USB cable into the computer, but not into the phone.
3. Hold HOME and POWER buttons
4. As soon as you are holding the HOME and POWER buttons, plug in the USB connector.